Process of treating synthetic polyamide textile materials with unsubstituted polyvalent phenols



United States Patent 19,2 9 6 Claims. '(Cl. 8--130.1)

This application is an continuation-in-part of application Serial No.133,564 which was filed on August 24, 1961, and which is now abandoned.

The present invention is directed to a finishing and dyeing process fortextile materials. More particularly, the subject invention delates to afinishing and dyeing process for threads, yarns, woven and knit-tedproducts which are made from synthetic polyarnides.

Textile materials commonly are not only dyed but are also subjected toother finishing operations in order to improve the feel, appearance, andwearing ability of such materials. As an example, stockings which aremade from polyamides, such as nylon, customarily are fixed withsaturated steam or hot air to preserve their shape and to make thestockings soft to the touch. The softness and feel of such products canbe improved even more by the use of particular softening agents. Organicswelling agents such as phenols or their aqueous solutions also improvethe surface properties and increase the dye absorption of syntheticpolyamides.

Although phenols improve certain properties of polyamide fabrics, it hasbeen found that the presence of phenols in the dye baths often causesthe color of the products to change under certain circumstances. This istrue, for example, when ladies hose are dyed with dispersion dyes suchas water-insoluble Celliton dyes. The swelling action of the phenolwhich aids the dye absorption and improves the finish of a product,changes the color tone especially in the case of light colors such asare used in manufacturing ladies hose. It has also been found that whenthe swelling of the textile products is begun with phenol and isfinished with special vivifiers, the polyamide products lose theirimproved feel after repeated washings and become soft and ragged unlessspecial wash resistant vivifiers are used.

It is an object of the present invention to provide a method of dyeingand finishing polymamide threads, yarns, and finished products in thepresence of phenol which avoids the disadvantages outlined above.

Other objects of the invention will become apparent to those skilled inthe art from the following detailed decription.

In .general, the present invention comprises the discovery thatpolyamide products having excellent properties can be produced if anunsubstituted polyvalent phenol and an aliphatic, anion-active compoundis present in the finishing or dyeing bath and if the dyeing orfinishing operation is carried out in an alkaline medium. Thesimultaneous presence of the phenol and the anion-active compound is ofcritical importance. If the textile materials are finished and dyed insuccessive steps, it is satisfactory to add the phenol .and thealiphatic, anion-active compound only to the finishing bath. In thiscase the finishing operation prepares the textile material in such amanner that under ordinary dyeing conditions and without other specialcomponents being present, unobjectionable dyeing takes place and thefinished product has a satisfactory feel and appearance.

Textile materials of polyamides which are dyed and finished in thepresence of a phenol and an aliphatic,

anion-active compound in an alkaline medium not only have a uniformcolor but also demonstate other valuable properties which distinguishsuch products from those treated only with a phenol. As an example,knitted articles of polyamide thread, particularly ladies hose, whentreated with a solution containing an unsubstituted polyvalent phenoland a hard soap at a pH of between 7 and 8 maintain their silklike feeland sheen after repeated washings. Furthermore, the appearance of suchproducts gives the impression that they have been treated with asoftener. The danger of runs or snags in the case of knitted articles isalso reduced by about one-third. Another manufacturing advantage whichis realized with respect to stockings treated with the phenol andaliphatic, anion-active compound in an alkaline medium is that suchstockings can be removed from their forms without difficulty and withoutthe use of a particular softener. This advantage is not obtain-ableusing phenol alone. For this reason the forming and fixing of thestockings may advantageously take place at the end of the manufacturingprocess as so-called postboa-rding. The possibility of combining thefinishing and the dyeing steps, simplifies the manufacture of theproducts and ofiers economic advantages in comparison with prior artprocesses in which the woven or knitted articles are especially treatedafter dyeing in order to make them suitable for sale and wear.

Textile materials of synthetic polyamides which are finished or dyed inaccordance with this invention have particularly advantageous propertieswhen they are treated in the presence of ortho, meta and para-dihyd-roxybenzenes. The heat resistance of such materials is greatly increased.Threads of hexamet-hylene diamine-adipic acid-polycondensation productsor of polycaprolactam which are finished in the presence ofortho-dihydroxy benzene demonstrate little, if .any, decrease in tensilestrength after heating for one hour at 200 C. In contrast, the tensilestrength of untreated threads of the same type drop from 20% to 40% ofthe original tensile strength when subjected to the same heatconditions.

The method of carrying out the subject process is quite simple,especially when the finishing step is combined with the dyeing s-tep. Asan example, stockings made of polyamide threads, after p-resetting(steaming) and sewing, can be boiled for one hour in a solution of 10grams per liter of phenol and 2.5 grams per liter of soap after whichthey are rinsed and dyed in a fresh bath. It is of advantage to combineboth the dyeing and finishing operations by adding the phenol andaliphatic, anion-active compound to the dye bath. in this process thestockings are placed in the boiling treating bath for one hour,whereupon the stockings a-re rinsed and postb-oarded. The operation iscarried out at an alkaline pH of between 7 and 8 which is the value ofthe solution if alkali metal salts of higher fatty acids are used as thealiphatic, anionactive compound. If another aliphatic, anion-activecompound is used, such .as a .sulfated fatty alcohol, however, theproper pH value is obtained by adding a caustic sodium solution or sodato the treating agent.

The subject process is suitable for use in connection with dispersiondyes, 2:1 complex dyes, acid dyes, or substantive dyes. The use of suchdyes in connection with polyamides is well known in the art.

Unsubstituted polyvalent phenols which can be used in the subjectprocess include pyrocatechol, resorcinol, and hydroquinone which arealso known as ortho, meta and para-dihydroxy benzenes, as well aspyrogallol and phloroglucinol. My preferred materials are ortho, metaand para-dihydroxy benzenes and the most preferred material isortho-dihydroxy benzene.

A wide variety of aliphatic, anionic compounds can be used in thesubject invention. Surface active agents are placed in one of threecategories. These agents are either anionic, cationic, or nonionic incharacter. If the elongated, low afiinity portion of the molecule of thecompound is included in the anion in aqueous solution, the substance istermed anion-active or anionic. The most common anionic aliphaticcompounds are soaps such as the alkali metal salts of fatty acids. Suchsoaps are formed from fatty acids containing from 8 to 22 carbon atomsand preferably from 12 to 18 carbon atoms. The fatty acids can be bothsaturated and unsaturated. Illustrative examples of soaps would includesodium and potassium, laurate, myristate, palmitate, stearate, andoleate.

In additon to soaps, other satisfactory anion-active aliphatic compoundsinclude sulfated fatty acids containing from 8 to 22 carbon atoms, andpreferably from 12 to 18 carbon atoms, sulfated fatty alcoholscontaining from 8 to 22 carbon atoms, and preferably from '12 to 18carbon atoms. In particular, such anion-active aliphatic compounds caninclude the sulfates or sulfona-tes of lauric acid, myristic acid,palmitic acid, stearic acid, oleic acid, dodecyl alcohol, tetradecylalcohol, cetyl alcohol, octadecyl alcohol, oleyl alcohol, and mixturesthereof.

The following example is illustrative of the present invention.

Example In this example 60 denier polyamide threads in the hank weredyed in a bath containing grams per liter pyrocatechol (brenzcatechin)2.5 grams per liter hard soap (sodium stearate) 1% Cibalan grey BL Thetemperature of the bath was raised from room temperature to boiling andwas held at this temperature for one hour. Thereafter the threads wererinsed in the customary manner. The threads had .a silklike and suboffrom about to 30 C. is brought to a boil in the course of from about 30to 60 minutes, and is maintained at that temperature for from one-halfto two hours.

As was pointed out above, the pH of the bath should be between about 7and 8. If soaps are used as the treating agent, the pH of the bath willbe maintained within this range without the addition of other materials.If sulfated alcohols, or the like, are used, however, it may benecessary to adjust the pH of the bath by the addition of caustic sodaor some other alkaline compound.

The finishing or dye bath should contain from about 9 to 11 grams perliter of phenol, and preferably 10 grams per liter of phenol, and shouldcontain from about 1.5 to 3 grams per liter of the anion-activealiphatic compound, and preferably from 2 to 2.5 grams per liter of theanion-active aliphatic compound.

As was pointed out above, the important features of the invention arethesimultaneous use of thephenol and aliphatic, anion-active compound intreating synthetic polyamide, and the fact that the treating bath shouldbe maintained at a pH of between about 7 and 8. Any anionic aliphaticcompound bearing .a hydrocarbon chain of from 8 to 22 carbon atoms, andperferably from 12 to 18 carbon atoms, can be used in the process. Thehydrocarbonchain can either be saturated or olefinically unsaturated.

Obviously many modifications and variations of the invention ashereinbefore set forth may be made without departing from the spirit andscope thereof, and therefore only such limitations should be imposed asare indicated in the appended claims.

I claim:

1. A process for finishing textile materials of synthetic polyamideswhich comprises: contacting said polyamide with a 'boilingbathcontaining an unsubstituted p'olyvalent phenol and an aliphaticanion-active compound, at a pH of between about 7 and 8.

2. A process as in claim '1 wherein the polyamide is maintained in theboiling bath for about one-half to about two hours.

3. A process for finishing textile materials of synthetic polyamideswhich comprises: contacting said polyamide with a boiling bathcontaining an unsubstituted polyvalent phenol selected from the groupconsisting of pyrocatechol, resorcinol, :hydroquinone, pyrogallol, andphloroglucinol, and an aliphatic anion-active compound selectedfrom thegroup consisting of alkali metal salts of fatty acids containing from 8to 22 carbon atoms, sulfated fatty acids containing from 8 to 22 carbonatoms, and sulfated fatty alcohols containing from 8 to 22 carbon atoms.

4. A process as in claim 3 wherein said bath contains from about 9 to 11grams per liter of the phenol and from about 1.5 to about 3 grams perliter of the anion-active compound.

5. A process as in claim 3 wherein said bath contains about 10 grams perliter of the phenol and about 2 to 2.5 grams per liter of saidanion-active substance.

6. A process as in claim 5 wherein said phenol is pyrocatechol andwherein said anion-active compound is stearic acid.

No references cited.

NORMAN G. TORCHIN, Primary Examiner. J. C. CANNON, Assistant Examiner.

1. A PROCESS FOR FINISHING TEXTILE MATERIALS OF SYNTHETIC POLYAMIDESWHICH COMPRISES: CONTACTING SAID POLYAMIDE WITH A BOILING BATHCONTAINING AN UNSUBSTITUTED POLYVALENT PHENOL AND AN ALIPHATICANION-ACTIVE COMPOUND, AT A PH OF BETWEEN ABOUT 7 AND 8.